After about 02:50 there is a short commentary by NASA Launch Weather Officer John Meisenheimer about the decision to first delay, and the next day to launch Explorer 1 (1958 α1 (now written 1958-001A), NORAD #4), the first satellite put into orbit by the United States, following the Soviet Union's successful Sputnik 1 and Sputnik 2.

He says:

At one time, they measured the jet stream wind at 227 miles an hour (365 kph) over the cape. Well, of course, it would have driven the rocket off course, Range Safety would have blown it up immediately. The next day my calculation showed there was a wave in the jet stream. By evening, there would be a window of opportunity. I convinced him that probably would do it. And so he said 'okay, we’ll listen to the kid go fuel the rocket.' And things went well.

Question: How did "the kid" (John Meisenheimer) calculate that there was a wave in the jet stream and Explorer 1 would be okay to launch? Is this based in part on the analysis of doppler radar data, satellite, data (humor), balloons, high altitude planes?

$\begingroup$It would have had to be weather balloons. The now-standard Jimsphere (spinoff.nasa.gov/spinoff1996/48.html) wasn't developed until later. Not writing an answer because I don't know about the calculation part.$\endgroup$
– Organic MarbleDec 23 '18 at 14:22

$\begingroup$@OrganicMarble Concur. As I am not a meteorologist either, I'm asking a group of professional meteorologists. Hoping to get an answer anytime soon now.$\endgroup$
– Jan van OortAug 27 at 10:15